A high reliability battery management system

Over a period of some 5 years Canadian Astronautics Limited (CAL) has developed a system to autonomously manage, and thus prolong the life of, secondary storage batteries. During the development, the system was aimed at the space vehicle application using nickel cadmium batteries, but is expected to be able to enhance the life and performance of any rechargeable electrochemical couple. The system handles the cells of a battery individually and thus avoids the problems of over, and under, drive that inevitably occur in a battery of cells managed by an averaging system. This individual handling also allow cells to be totally bypassed in the event of failure, thus avoiding the losses associated with low capacity, partial short circuit, and the catastrophe of open circuit. The system has an optional capability of managing redundant batteries simultaneously, adding the advantage of on line reconditioning of one battery, while the other maintains the energy storage capability of the overall system. As developed, the system contains a dedicated, redundant, microprocessor, but the capability exists to have this computing capability time shared, or remote, and operating through a data link. As adjuncts to the basic management system CAL has developed high efficiency, polyphase, power regulators for charge and discharge power conditioning

Payload system tradeoffs for mobile communications satellites

System level trade-offs carried out during Mobile Satellite (M-SAT) design activities are described. These trade-offs relate to the use of low level beam forming, flexible power and spectrum distribution, and selection of the number of beams to cover the service area. It is shown that antenna performance can be improved by sharing horns between beams using a low level beam forming network (BFN). Additionally, greatly increased power utilization is possible using a hybrid matrix concept to share power between beams

The application of amino acid racemization in the acid soluble fraction of enamel to the estimation of the age of human teeth

Estimation of age-at-death for skeletonised forensic remains is one of the most significant problems in forensic anthropology. The majority of existing morphological and histological techniques are highly inaccurate, and show a bias towards underestimating the age of older individuals. One technique which has been successful in forensic age estimation is amino acid racemization in dentine. However, this method cannot be used on remains where the post-mortem interval is greater than 20 years. An alternative approach is to measure amino acid racemization in dental enamel, which is believed to be more resistant to change post-mortem. The extent of amino acid racemization in the acid soluble fraction of the enamel proteins was determined for modem known age teeth. A strong correlation was observed between the age of the tooth and the extent of racemization. No systematic bias in the direction of age estimation errors was detected. For the majority of teeth analyzed, the presence of dental caries did not affect the results obtained. In a minority of cases, carious teeth showed a higher level of racemization than would be expected given the age of the individual. These results indicate that amino acid racemization in enamel has the potential to be used in age estimation of skeletal remains. (C) 2007 Elsevier Ireland Ltd. All rights reserved

Similar Sublattices and Coincidence Rotations of the Root Lattice A4 and its Dual

A natural way to describe the Penrose tiling employs the projection method on the basis of the root lattice A4 or its dual. Properties of these lattices are thus related to properties of the Penrose tiling. Moreover, the root lattice A4 appears in various other contexts such as sphere packings, efficient coding schemes and lattice quantizers. Here, the lattice A4 is considered within the icosian ring, whose rich arithmetic structure leads to parametrisations of the similar sublattices and the coincidence rotations of A4 and its dual lattice. These parametrisations, both in terms of a single icosian, imply an index formula for the corresponding sublattices. The results are encapsulated in Dirichlet series generating functions. For every index, they provide the number of distinct similar sublattices as well as the number of coincidence rotations of A4 and its dual.Comment: 8 pages, paper presented at ICQ10 (Zurich, Switzerland

Factors to be considered in planning public relations programs for congregational churches

Thesis (M.S.)--Boston Universit

An Automated Approach for Predicting RF Signal Margins for Missile Flight Tests

A computer system is described which accurately predicts RF instrumentation system signal margins for missile flight tests. The RF signal margin predictions are a function of the missile trajectory and the parameters of the range balance equation which are explained in detail. The mathematical development of the system is given as well as a presentation of data from a recent missile flight test at AFETR. A discussion is presented which illustrates how this system may be used as a flight test program planning tool and as an instrumentation system performance analysis device applicable to missile flight test programs

PoN-S : a systematic approach for applying the Physics of Notation (PoN)

Visual Modeling Languages (VMLs) are important instruments of communication between modelers and stakeholders. Thus, it is important to provide guidelines for designing VMLs. The most widespread approach for analyzing and designing concrete syntaxes for VMLs is the so-called Physics of Notation (PoN). PoN has been successfully applied in the analysis of several VMLs. However, despite its popularity, the application of PoN principles for designing VMLs has been limited. This paper presents a systematic approach for applying PoN in the design of the concrete syntax of VMLs. We propose here a design process establishing activities to be performed, their connection to PoN principles, as well as criteria for grouping PoN principles that guide this process. Moreover, we present a case study in which a visual notation for representing Ontology Pattern Languages is designed

The geology of the Oceanographer Transform Fault

A detailed survey of the Oceanographer transform fault and environs at 35º N, 35ºW has yielded detailed information with respect to the generation and evolution of seafloor at a slowly accreting plate margin. From this data detailed bathymetric maps and maps of depth to basement have been constructed for a swath of seafloor 1800 km long and 100-200 km wide centered about the offset region. This data was used to subdivide major phases of seafloor spreading during the Tertiary. The ridge crest and all major topographic features near the transform appear to be affected by their proximity to the transform. The ridge crest widens and deepens towards the transform, and the rift valley walls are higher when they lie on the transform side of the valley than when they lie on the fracture zone side of the rift. Based upon the observed topographic effects the physical properties of the crust and upper mantle must vary markedly near the transform. Constraints provided by a combined ALVIN/ANGUS field program in the summer of 1980 indicate that the present zone of decoupling between the North American and African plates is located in the center of the transform valley; the zone of decoupling is less than 2 km wide, and is defined most often by discontinuous, variable degraded elongate fault or slump-degraded fualt scarps in sediment.-Vertical tectonism and mass-wasting processes dominate near the axial deep whereas deposition and erosion dominate in the terraces and the upper wall province. The petrologic data and the rock distribution data confirm that the crust near the Oceanographer transform is thin and even, perhaps discontinuous and indicates that the mode of crustal formation is likely to change significantly near transforms. Spectacular bedforms including abyssal furrows, dunes, longitudinal and transverse current ripples, and wave ripples are abundant. Except for the furrows these bedforms are concentrated in the very rugged, upper wall province of the transform. Chapter 3 presents a model for the formation of transform topography. This model hinges upon the assumption of a curved zone of decoupling between the plates near each ridge-transform intersection. This curvature gives rise to a geometric peculiarity which requires a gap to open between the plates. This gap conceivably should alter significantly many of the physical properties of the transform such as its depth, the height of the crestal mountains, the presence and width of any transverse ridges, and gradients of the seafloor into the intersection deep. Many of these properties vary in a fashion consistent with the model